1. Field of the Invention
The present invention relates to a projection apparatus suitable for a Digital Light Processing (DLP) (a registered trademark) projector apparatus using semiconductor light-emitting elements.
2. Description of the Related Art
In order to reduce thermal damage to a fluorescence layer remarkably even if a beam-light-based excitation source is modified to produce a higher power, the technique for causing a motor and a crank mechanism to swing a fluorescence wheel on which a plurality of fan-shaped fluorescence substances have been arranged and its rotary drive unit so as to cyclically move the position of a fluorescence substance irradiated with beam light has been considered as disclosed in, for example, Jpn. Pat. Appln. KOKAI Publication No. 2010-164846.
In the technique written in the above patent document, the position on a fluorescence layer in which a spot of beam light is cast is moved, thereby preventing the fluorescence layer from being damaged thermally. This type of projector has always been requested to improve the brightness of a projected image more by modifying the semiconductor light-emitting element used as a light source to produce a higher power. However, to satisfy the request by the technique written in the patent document, the mechanical structure of the apparatus has to be made larger and more complicated. Therefore, there is a limit to satisfying the request.